The Panel Study on Homelessness, being conducted in Ottawa, is a first attempt at examining the pathways into and out of homelessness by following a cohort of homeless persons over time. The research objective for the first wave of the study was to interview a representative sample of current residents of Ottawa emergency shelters in order to gather descriptive data on demographic characteristics, housing history, health status and health and social service utilization. A sample of 416 homeless participants was interviewed between October 2002 and May 2003. There were five subgroups of participants: adult men, adult women, families (defined as at least one adult with at least one child under the age of 16, male youth and female youth. This research project used the panel study to develop and empirically validate a methodology for locating as many participants as possible over time.